The present invention relates to a shaking test apparatus and a shaking test method in which a part of a structure is shaken (vibrated) by a shaker (vibrator) to perform a shaking test on the structure, and the whole structure is numerically modeled and analyzed on the basis of the shaking test result thus obtained.
A shaking test on a structure has been hitherto performed by vibrating (shaking) the whole structure of a read object or a model of the whole structure of a model of the object using a shaker (vibrator) According to this method, every time a structure is partially improved or the specification thereof is changed, it is necessary to carry out a shaking test on the whole structure once again, and thus the cost and time required for developments increase more and more. In the case of a large-scale structure, it is difficult to perform the shaking test on the whole structure because of limitation of the capacity of the shaker. In order to avoid this disadvantage, there has been recently proposed a method of using both a shaking test and a modal analysis in combination on the basis of the building block approach.
For example, in Japanese Laid-open Patent Application No. Hei-8-82571, it is suggested that the whole structure should be subjected to a shaking test in advance to determine the shaking modes of the whole structure and then a finite element analysis is applied to an altered place of the whole structure to correct the shaking modes of the whole structure, thereby estimating shaking responses. Further, in a collection of papers of xe2x80x9cJapan Society of mechanical Engineersxe2x80x9d (C-edition), Vol. 63, No. 616 (1997-12), pp4134-4139, it is proposed that a model of a partial structure should be determined by experimental modal analysis, the model thus determined and numerical models of the other parts of the structure are then combined to simulate the overall system, and then the partial structure is shaken using the simulation result. Further, in Japanese Laid-open Patent Application No. Hei-5-10846, it is proposed that a partial structure should be subjected to the shaking test and the portions other than the partial structure are then subjected to modal analysis by using the numerical models thereof, thereby performing both the shaking test and the modal analysis in cooperation with each other.
In the case of the method disclosed in the Japanese Laid-open Patent Application No. Hei-8-82571, the altered portion is handled by numerically modeling it and thus various alterations can be easily made. However, when the shaking characteristic of a partial structure is complicated, it is difficult to accurately model the partial structure.
In the case of the method disclosed in the collection of papers of xe2x80x9cJapan Society of Mechanical Engineersxe2x80x9d (C-edition) Vol. 63, No. 616 (1997-012), pp4134-4139, since the shaking characteristic of the partial structure is first identified, it is difficult to apply this method to a case where the characteristic of the partial structure is varied in accordance with the shaking level or a case where the characteristic is varied due to shaking.
In the case of the method disclosed in Japanese Laid-open Patent Application No. Hei-5-10846, a measured response from a partial structure is directly used for time record calculations of the numerical model, and thus this method can support the variation of the characteristic of the object being examined. However, this method has a problem in that the response of the shaker is delayed.
The present invention has been implemented in view of the foregoing problems associated with the conventional techniques, and has an object to provide shaking test apparatus and a method of performing a shaking test for combining and estimating the shaking characteristic of a partial structure of an object under test obtained through a shaking test and the shaking response of the whole structure which is numerically modeled, thereby estimating-the shaking response with high precision.
Another object of the present invention is to enable estimation of the shaking response with high precision in a so-called hybrid shaking test for combining a partial structure and a numerical model to estimate the shaking response even when the shaking is carried out at a high frequency.
A further object of the present invention is to enable estimation of the shaking response for even a structure having a high non-linearity in a so-called hybrid shaking test for combining a partial structure and a numerical model to estimate the shaking response.
In order to attain the above objects, according to a first aspect of the present invention, a shaking test apparatus for carrying out a shaking test on a structure by using a partial structure and a numerical model which is virtually connected to the partial structure is characterized by comprising: shaking means for vibrating (shaking) the partial structure; displacement detection means for detecting the displacement of the partial structure thus shaken by the shaking means; load detection means for detecting a reaction force from the partial structure; and operation means for identifying a vibration model corresponding to the partial structure on the basis of the displacement and reaction force thus detected, combining the vibration model and the numerical model with each other to build the model of the whole system corresponding to the structure and operate the shaking response of the whole-system model.
In the shaking test apparatus, it is preferable that the operation means includes means for inputting an input signal when the shaking response of the whole-system model is operated, and the operation means is provided with shaking target selection means for changing the shaking condition of the partial structure to be shaken, and the shaking target selection means changes the shaking condition so that by using the same partial structure, the shaking test can be carried out on a different partial structure.
In order to attain the above objects, according to a second aspect of the present invention, a shaking test apparatus for carrying out a shaking test on a structure by using plural partial structures and a numerical model, which is virtually connected to the partial structures, comprises shaking means for shaking each of the partial structures; displacement detection means for detecting the displacement of the partial structures shaken by the shaking means; load detection means for detecting the reaction force from the partial structures, the shaking means, the displacement detection means and the load detection means being provided for each of the plural partial structures; and operation means for identifying the vibration models of the partial structures on the basis of the displacements and the reaction forces thus detected, combining the plural vibration models and the numerical model to construct the overall-system model corresponding to the structure, and calculating the vibration response of the overall-system model.
In order to attain the above objects, according to a third aspect of the present invention, a shaking test apparatus for carrying out a shaking test on a structure by using a partial structure and a numerical model which is virtually connected to the partial structure comprises: plural shaking means for shaking the partial structure; displacement detection means for detecting the displacement of the partial structure shaken by each of the shaking means; load detection means for detecting the reaction force from the partial structure, the displacement detection means and the load detection means being provided for each of the shaking means; and operation means for identifying the vibration models of the partial structure on the basis of the displacements and the reaction forces thus detected, combining the plural vibration models and the numerical model to construct the overall-system model corresponding to the structure, and calculating the vibration response of the overall-system model.
In order to attain the above objects, according to a fourth aspect of the present invention, a shaking test apparatus for carrying out a shaking test on a structure by using a partial structure and a numerical model which is virtually connected to the partial structure comprises: means for creating the vibration model corresponding to the partial structure: and a shaking apparatus for the partial structure for which correction data for correcting the vibration model can be obtained.
In order to attain the above objects, according to a fifth aspect of the present invention, a structure shaking test method for carrying out a shaking test on a structure by using a partial structure and a numerical model which is virtually connected to the partial structure comprises the steps of: creating the vibration model corresponding to the partial structure; creating an overall-system model comprising the vibration model and the numerical model; and correcting the overall-system model on the basis of the shaking test result of the partial structure.
In order to attain the above objects, according to a sixth aspect of the present invention, a structure shaking test method for carrying out a shaking test on a structure by using a partial structure and a numerical model which is virtually connected to the partial structure comprises: a first step of constructing the overall-system model corresponding to the structure from the vibration model corresponding to the partial structure and the numerical model; a second step of calculating a vibration response for the overall-system model constructed on the basis of a shaking input signal to be applied to the structure; a third step of generating a shaking signal of the partial structure on the basis of the vibration response and shaking the partial structure using a shaker; a fourth step of renewing and identifying the vibration model on the basis of the displacement and load of the partial structure thus shaken; a fifth step of reconstructing the overall-system model on the basis of the renewed vibration model; and a sixth step of calculating the vibration response for the overall-system model and repeating the third to sixth steps.
It is preferable that a step of preliminarily shaking the partial structure on the basis of any signal is provided to identify the vibration model prior to said first step, a plurality of vibration models are prepared, and the method is allowed to handle the plural vibration models by varying the shaking condition of the same shaking means.